This invention relates to an apparatus and method for automatically transferring bacterial specimens from specimen containers to the surface of culture medium plates, and to streaking such bacterial samples in programmable patterns to produce isolated bacterial colonies. In particular, it provides for the precise deposition of an inoculant at a specific location on the surface of a culturing medium, and the subsequent re-entry of a streaking tool at this same location to effect streaking. It further provides a versatile system for varying the streaking procedure in accordance with the specimen being treated. This invention also relates to an apparatus and method for automatically removing the top of either xe2x80x9cjar-typexe2x80x9d specimen container or a xe2x80x9cswab-typexe2x80x9d container while simultaneously identifying the specimen.
The isolation and identification of a sample of a bacterial specimen has for many years involved the inoculation of the sample onto a culture medium. The type of culture medium used and the method by which it is placed on the culture medium depends on the type of specimen being handled.
This invention relates in one aspect to two types of specimen containers. One type of specimen container, the xe2x80x9cswab-typexe2x80x9d, consists of a stylus- or wand-like stem attached to a cap removably fitted onto a separate, test-tube like container. A swab fixed at the opposite end of the stem from the cap is coated with and carries the bacterial specimen during transfer to the cultivating medium. The other type of specimen container, the xe2x80x9cjar-typexe2x80x9d, consists of a jar- or bottle-like vessel containing a liquid specimen, such as urine, a portion of which is to be transferred to inoculate the cultivating medium.
The receptacle containing the swab is typically a transparent tube having a closed end and an open end providing a narrow mouth. The swab shaft carries its absorbent pad xe2x80x94the swab tipxe2x80x94 at the outer end of the stem remote from the cap end. While the stem extends into the tube from the cap when the cap is in place on the tube, variations in manufacturing may cause the stem to be deflected sideways. Hence, upon removal of the swab stem from the tube, the stem may deflect from alignment with the central axis of the cap causing the displacement of the swab tip sideways. The precise location of the swab relative to the cap and the axis of the cap will then be unknown.
Inoculation from a xe2x80x9cswab-typexe2x80x9d container requires identification of the specimen type, removal of the cap (with the stem and swab attached) from the receptacle and rolling the swab end (which is coated with the specimen) over a portion of the surface on a culture medium which is suited to the specimen. This transfer must occur at a specific deposit location and the sides of the swab should be equally exposed to the surface of the cultivating medium, without disrupting the surface, during transfer of bacteria to the deposit location. If the swab stem is bent, this operation is difficult to effect through automation.
An object of this invention is to effect inoculation of the cultivating medium at a deposit location whose position is recorded, followed by effecting streaking automatically, using the recorded deposit location to guide an automated streaking tool.
After inoculation occurs the swab is normally returned to its original container. In doing so the swab must be aligned with the mouth of the test-tube to prevent contamination of the exterior portion of the tube. This alignment must be arranged even when the swab stem is bent.
Inoculation from a xe2x80x9cjar-typexe2x80x9d container requires removal of the cap, extraction of a specified amount of liquid, e.g. urine, and placement of an amount of liquid onto the deposit location on the culture medium""s surface. The container with its remaining liquid is then recapped and conveyed away for storage.
Inoculation from a xe2x80x9cjar-typexe2x80x9d container requires identification of the specimen (as by reading markings on the outside surface of the container), removal of the cap, extraction of a specified amount of urine, placement of that amount onto a defined area on the appropriate culture medium and recapping the jar. This procedure is time consuming, inconsistent and biohazardous. Automating the entire procedure would address all three of these concerns. Two critical parts of the inoculating process for the xe2x80x9cjar-typexe2x80x9d specimen container are the uncapping of the specimen container and the reading of the data imprinted on the container.
The isolation and identification of a specimen requires that the specimen sample be distributed or spread over the culture mediumxe2x80x94xe2x80x9cstreakedxe2x80x9dxe2x80x94in a one of several prescribed patterns that is correlated to the specific specimen. These patterns must provide an increasing dilution of the sample and are effected by a streaking tool. Once so streaked the prepared medium plates can then be incubated to promote bacterial growth. This bacterial growth can then be examined or subjected to further tests for isolation or identification of the bacteria type(s) present in the specimen.
Proper preparation of the media plates is biohazardous, time consuming and difficult to perform manually in a consistent manner. It is also difficult to maintain consistency between the techniques used by different technicians or even between different samples prepared by the same technician at different times.
An object of this invention is therefore to provide a method and apparatus for inoculating medical specimens from either the xe2x80x9cswab-typexe2x80x9d or xe2x80x9cjar-typexe2x80x9d containers onto culture media which closely simulates the effect of established manual procedures, but with improved consistency, accuracy and safety.
A further objective is to provide a method and apparatus for removing a specimen swab from a container, and to provide for reading data on the container.
A further objective is to provide a method in which a specimen swab, e.g. an elongate element, which is somewhat bent from its nominal position may be properly applied to the surface of a cultivating medium and then be reinserted into its originating receptable consistently and accurately.
A further object of this invention is to provide a method and apparatus for streaking bacterial samples in programmable patterns corresponding to the actual specimen being evaluated, which closely simulates the effect of established manual procedures, but with improved consistency, accuracy and safety.
Yet a further objective is to provide an efficient method and apparatus in which the cap of a jar-type container may be removed in parallel with reading data that has been imprinted, encoded or otherwise embedded on the container. An additional objective is to provide a method and apparatus in which the existence of a sufficient amount of liquid specimen in the container may be verified.
The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention in its broadest and more specific forms will then be further described, and defined, in each of the individual claims which conclude this Specification.
A preferred embodiment of this invention provides an automated overall specimen container transport, handling and inoculating system which integrates and improves standard procedures and techniques for transferring bacteria to a cultivating medium, followed by streaking of such bacteria on such medium using automated means. Thus a specimen delivery system conveys a sample specimen to a deposit location on a culture medium, recording the location of the deposit location in a memory. A streaking mechanism then effects streaking using the recorded deposit location data to guide the streaking tool.
According to a further feature of the invention, the mechanism of the system may dispense culture media as called for by the specimen""s embedded data and identify or label each dispensed container of media so that it can be correlated with its corresponding specimen. A sample of the bacterial specimen on a specimen carrier e.g., a swab or pipette, is then transferred to the culture medium by a specimen sample delivery system or xe2x80x9cspecimen delivery systemxe2x80x9d. Streaking is thereafter effected in accordance with the procedure appropriate for each specific specimen.
As indicated, a special feature of the invention is that a specimen delivery system which is computer controlled is used to convey the specimen from its original container to a deposit location on the culture medium. A computer controlled streaking tool carried by a streaking mechanism is then directed to the same deposit location based upon digitally stored data corresponding to the precise position of such deposit location. The streaking tool may then engage the culture medium and effect streaking in accordance with the pattern suited for the specific specimen with which the culture medium has been inoculated.
The specimen delivery system brings the specimen carrier with its bacterial sample in contact with the culture medium in a controlled manner which ensures that the bacteria are properly deposited at the deposit location. For xe2x80x9cswab-typexe2x80x9d specimens comprising a stylus- or wand-like swab stem attached to a cap and carrying a swab coated with the bacterial specimen, the swab is so xe2x80x9cfixturedxe2x80x9d that when it is brought into contact with its corresponding culture medium, the transfer of bacteria occurs at the deposit location in the correct manner.
To achieve such fixturing of the swab according to one feature of the invention, a capped swab-containing receptacle is first placed into a holding fixture by a robot manipulator. The same manipulator then grasps the cap and withdraws it and the attached swab stem from the mouth of the receptacle. The swab and swab stem are then presented to a tip location device. The exact location of the swab located at the stem tip and its orientation with respect to the cap""s position is determined by a visual examination effected by the tip location device. This exact tip location with respect to the end effector of the grasping manipulator is then stored in a digital memory to subsequently be used to control the specimen delivery system in positioning the swab on the culture medium at the deposit location in order to properly inoculate that medium. Then the specimen delivery system is used to reinsert the swab into the receptacle, again using the digitally stored data defining the location of the swab at the stem tip to ensure that the swab passes into the mouth of its container without contaminating its rim or exterior surface.
In one embodiment, the swab tip is located using a camera and a single back-lighted surface. A 90xc2x0 rotation about the axis of the element is effected and two images are taken by the camera to establish the location of the swab tip. In another embodiment, the swab tip is located using a single camera image frame, two mirrors, and two back-lighted surfaces whereby two separate views of the swab tip are effected simultaneously. In yet another embodiment, a laser range camera may be used to scan and establish the location of the swab tip. From these measurement procedures the location of the tip is determined and stored in the memory of the digital controller.
The swab tip is then carried by the specimen positioning system to the deposit location whereat the outer surface of the swab is rolled against the surface of the culture medium to transfer bacteria to the deposit location. During this transfer, the swab in one variant is fixtured to maintain the required degree of contact with the culture medium surface by the action of the specimen delivery system in adjusting the location of the cap laterally while the cap is being rotated. This adjustment is effected using the data for the location of the swab tip with respect to the cap, as stored in the digital memory.
Rather than so controlling the position of the cap while it is being rotated, the cap may be rotated at a stationary location if the swab tip is mechanically fixtured to ensure that it is positioned along the axis of rotation of the cap. This may be effected by extending a guide, such as a wire with a loop, from the specimen delivery system so that the loop guides the swab tip into alignment with the axis of rotation of the cap during transfer of bacteria to the culture medium.
For xe2x80x9cjar-typexe2x80x9d containers, once its cap is removed, the specimen delivery system uses a pipetting tool as the specimen sample carrier to extract a volume of liquid from the open container and then deposit a volume of this liquid onto the surface of the culture medium at the deposit location. Again, the specimen carrier xe2x80x94the pipetting toolxe2x80x94is so fixtured that the robot manipulator as the specimen delivery system places the specimen precisely at the deposit location. As previously described, the position of the deposit location in space is recorded in a digital memory for subsequent use in further operations.
To present the jar-type containers to the specimen positioning system, a container manipulating device grasps the cap of the specimen container while the container is rotated by a rotating jar holder. The container manipulating device raises and removes the cap of the specimen container to one side once the rotating holder for the container has rotated it sufficiently so as to cause the cap and the receptacle to disengage. During this rotational motion, a scanning device located to one side of the holder/reader platform may conveniently read specimen-identifying indicia that has been previously imprinted, encoded or otherwise embedded on the side of the specimen container. A similar procedure may also be provided for reading indicia carried on the side of tubes containing swabs.
Provision is included for verifying the amount of specimen in the container. Provision is also provided for replacing the cap on the receptacle of the specimen container after the sample has been extracted.
As a particularly convenient arrangement, a jar-type container may be delivered to its lid-opening station on a conveyor, and the removal of the lid and extraction of a specimen sample may be effected with the jar container remaining on and supported by the conveyor.
Once a sample of bacteria has been transferred to the deposit location, streaking is then effected by a streaking tool which is carried by the streaking mechanism to the deposit location. The control system for the streaking tool uses digitally stored data in order to carry the streaking tool to the deposit location, optionally using a common robotic manipulator. The streaking pattern then effected is computer controlled to correspond with the identity of the specimen as obtained from the specimen container.
The deposit location, whether by application from a swab container or jar-type container can be stored in a suitable xe2x80x9cmemoryxe2x80x9d plus also specimen identification.
The streaking apparatus of the invention with its computer control system is versatile and may adopt a full range of streaking patterns. This feature, combined with the capacity to accept specimens in differing types of containers renders the apparatus of the invention highly versatile.